SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '687daec13b045858f35cb9a7b81145d9f366d2a3ba1eb9772a107678a9294871' 
  AND token = 'Ajkyp9EkXhpG+fT1DGSVat3eKXDLdg3nVQcDDQC2J5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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