SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f81c3f354520cbfc10a3cd91b08ecfc893350fe69496a1a1161c4a9aa4966f5' 
  AND token = 'lYqbIemvzQON/aIJDtdXOwiC4DYmxHtd5T8y+vSnP4w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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