SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c17e9223cc6030dee31755df8c6d29bbbdb8f6d0af70c7db21fbab1535bb0732' 
  AND token = '+VWlQfJ2KR686ROWDn7mhSWTcdhqdk6mtcexomlPw8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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