SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c6d0918c1610d1973dbd1b0ddad9fb6d9ae4a4ad0950d1374ccb9b2bac948309' 
  AND token = '+NUrJWKqYAqOzgfrRm2x70A1kKSM/+AUB7C+/LZhmSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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