SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f7c3a50718586d88318917342640f9e5a4b0b18488a81446d030c2e81927b3e' 
  AND token = 'wvRXBHjWLwzYM6u4lZ6NW9NcNrU2FvglxdYny7bCbyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}