SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd118bd7c0b5d9882f90c5c7067a37dc5d3cc52bc9c6afeeb77e5ecaa79d96323' 
  AND token = 'qj43a/ZpKp8h9MIMU8ZGnpV4BTvWNsPhE2UohYMCx4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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