SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1f3f9a56d4df1189fc9e2ad813cb5b59a1e13054c309d9a74fbd4b53dce7dd6' 
  AND token = 'BBV+b/mqftgwhJk2d3PQ+ilHWTgadCvDBwU8g3mxmpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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