SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cf82af22788903011f347c55a9acecd515b6e4cb8db0f1a5bdd56249d1510b8' 
  AND token = 'oiwRVkOmD9bWxH8oxf6oTmFli1LuB5Dp7+hksMxz3EM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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