SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dd5d915dc781bd6952b444771ad80d9ee6256a945e3de22592706bc2df5ea96a' 
  AND token = 'RUEfWKTSBUZ6EFnRbDkxep+SSrHXSHXREBBors6imbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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