SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5d93e5c653fdb3bfbd51086939ec8ae2a3d6fae6b9a441ea9580aaeea0c2400' 
  AND token = 'ZD5z/mtl5AuVH6iAoKFMPx76v9hJpFV0teUPgZhFwXs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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