SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3fb7f5576ab14d544abe3f9b36fef0d42ecc36de89919b1ad185ed52f659d0b' 
  AND token = '7bj4ptF+xKBau+E/R+PWeowxCZXSvwpBRu2wghGrFLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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