SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '919285adfec24a8db1b59712a8f2782625345cced97ad753cade89e49671d953' 
  AND token = 'oO4zMYqkWH+hfsHjeB0rE+1CqXAmeQPOTxMQgNWxYYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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