SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fc353316cca3b76fecb0f45e9d39f4af5b100b55820f249270f5a4cc8e2c620' 
  AND token = 'eyEJYgfA95DtN8F2mruVEYhnHw38XYIYNT0RgchbHIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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