SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b79a32cba29d7af8374e1d282a0646f1779e1a2f90c2349226f57a3d2ae9b70' 
  AND token = 'cDP8ZYyE6rYNobXJSEASApemudCIDGBXHklIiD+CZXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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