SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '894362552b0601a38a7a77b12e9e4507d5cf0f5b660b9d97a419eba87a4b6dce' 
  AND token = 'uEBMWsAnCJwC0jIP/ioWGKTjmmWOeLLWCl3YAHVy0rQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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