SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dd26c83570bff0162df3cb70715ef75faa884222bab56f4e533d112106648ad' 
  AND token = 'ihBUzMthwSWrTYpKyhsnSalf6oZAMiZJY6MgMV2JT6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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