SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e9cdcc6b1bd16416ea31cb8b697c9dc53ce9eb56087823df4e49df815513c54' 
  AND token = '/0mAAMGaFfulRXGAJc/T9okFgRZGzttnTovJaXBq8Qc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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