SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fb07b735fd99f804a13833ceb840d4df3976d696a771fed0fae967a3cb67669' 
  AND token = 'vrTdkT09n5fCKBwZ7HKMttjHCB1ynpYbK391rGGnGOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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