SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '32cf0cdca9aba9871671e1c305076491f48c1d40fe2481a2cfa5fb2f3e982872' 
  AND token = 'D3CIfzWdz7zJXwJj75FELdwFj8XBPoUlYIzDGwmlgfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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