SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fd6ad16cfe4d251db32b7117af6294a7762235026e9b3cb838e51f583296495' 
  AND token = 'HEEQniHxTclNHr5muPWk1YJJm8MN5sEtCAbHOTjj8+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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