SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '874b3e12f3929c51f01e8b3214ebafb896719749e65cfcab262a9b9305bdf215' 
  AND token = 'iYB9vW6DqubDJPcsiKizkyqLLvmNopfZv3xMIPkWGC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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