SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f89ccb312fb4ae1c7a246e1930df0317cb460bc0237e969db631ee115a703677' 
  AND token = 'tfr3OtpQJhTDGyIbxF2NhoNwVGiZDd70J+4EAXcw5d4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}