SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aa4ea04eefb331e486c862325c30671d4ae7cdfa391bb1571ee32f2ec17c2b7' 
  AND token = 'JMeu+I5ImXj674XQo7FoOveKMBX3ORps346fi3O9xcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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