SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ae42f4ca08941dfa9abab8d0f3e17d896894094e9abde117690f8266e21b49e' 
  AND token = '6LaGl7V324cnFAdK56dTFZ9tdyhkMffNev+fz6pABfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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