SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '191bbc148c8fe5d88dd9ae04246580c5a16605f38ac1782f086593a9a488def2' 
  AND token = 'T/Kx7QpQHTDOI9QFJv+Pko1U7rEWHF3JjBGjXaenbMY=' 
  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"
    }
  }
}