SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '035e3d142a5b8c1494432621928f8bd0083a80d07401d3431d2fc200425c66e2' 
  AND token = 'r8ILz/3JYu2dKp4btM57L09A2CaZ4M4lgWiM8IsyoCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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