SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7398bd4b1cfd4cad3d9acc728907bdf508993c31c536e11277d418afb2b9565f' 
  AND token = 'haWetoSs2rnYWI6d2HDT3Om8e89phQtDihXhEvnarzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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