SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd8269a0e7b03c2dcba1be643c3282aa2998ed99d9fae894d1fd2045884e4a73' 
  AND token = 'xEH+Iay7xSWQvQl7KzzTU55kwft8NXLJ096GR8f2iGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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