SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79617cb47232a246670ada350fa3db766980e4b200601e1aecce0b9416cd464b' 
  AND token = 'OXulm5xu/DltdmXcp+7m+6lZZAg+eeSUsMz2ETbcopA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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