SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '189d6237a8ccf2b8fe2a572b77f412d903d6c7a37a9f1d27d5c903f96ee92651' 
  AND token = 'mKgO0z3IxpvYwmDUgG9pNWr5Q9BAvYkhgz9g0LZkhGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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