SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68aabdb3a1ec5c2635fdb0093faa531b470cbb5d1808b51468f2311dcead447f' 
  AND token = 'jgGqMIfWSScGlFqdrvMNhZMWET9yrAbrJBR2i7f3r8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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