SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14b34f1489b1302702a109d6be894bd5a2358989ed4238f76f9f4683cb253683' 
  AND token = 'qNz7X9b4E89A/bIXBf+rDAnj7JIv2dc/IR1vJ72f+sk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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