SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27ec5f781ba39f25e215694a8cac59a77f3220514fec3f53848e6e677c6cb616' 
  AND token = 'fGvNWgy1wGlcoDUgU9uhrbVXVhmggyHalC4hEAWcaFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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