SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34054dc60f3277567622369920aa9d5299d6ad0730f847f2507ca4eafa01f7f8' 
  AND token = '76cfMjh58OIf8fDIFB7L5VMo1jfvBw+AcNVnpOzNUac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}