SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e59a66fd2293bba374587f2829ea9ca14c11f0f34803da96e637c7d588eadded' 
  AND token = 'YYuxdEKswjONUvjBZcQ3Rh/kPcrgMufqeW2Sg4kwlXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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