SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e21306d0de1a92a80bfa03c3c6fe36a6e2828e0cb25341bd6ac815f9ccf4076e' 
  AND token = '6Cl71nRYm3dWIz+nbHyRi+13wG0SVgTglYYm5B9L3lU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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