SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '855e81102241b6944e15a8e2303647d710f3881b022565cb3708e5987fccba0d' 
  AND token = 'PgYkdJ0m5dNoc/U/VpZfLW+G4CXi9TnPBnYVSFnJavs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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