SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47a7ec9352999fbe5d47e094edcc9b3391809fffd1ca5bb62a31ff44f2ca8114' 
  AND token = '2Y6i2dnl+FmrrmSRPnYGTDnUoa5jef0gYv8t2R/44Ao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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