SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c879534042431ffdfd9e29c4be3e5f9cafba74a1ce75f608084dfca40a4fe4ad' 
  AND token = 'OpUAvCUC1hNVmZ26VTbZrVjDpOt2hZQEJnhFqOq7CI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}