SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1cf9e375d192bd746b15349d726366a7a1517ce2ad1739bede8917812417431' 
  AND token = 'dnXpizrA9ISvLy9gjHKtdUCeKuKQqykX1AIcwkJ2U04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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