SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7436eda7330b99e6cd6678710ac36f5fbcd34e94836672348c6ecd8567c97296' 
  AND token = 'C3LKBjFZvgbV4D3ja6ivrndR1AV8FgpowjIyoBMiZNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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