SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c3ca64ae482eb91bebf9a6feb9f22dd43b12a407793dda66240234150bd4c24' 
  AND token = 'BBY1Pe/nvphwxS+vW1XY9e+PSdNTYnGQ9/KKEX4Jkrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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