SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4f7855226d257b1a847f050246eb78a93c89b3bc817a4d760c8f57514d7797b' 
  AND token = 'HLxu43BZFpXchwRRAvOmc25WdYpZfMYzSjsbhRVZiDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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