SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7d1cab581b4b9781480776b2e5927801bd45161a8525340ab974f2a8ccbf604' 
  AND token = 'desohWmXujRy4JaOLxxmZ5LLcgQgx/UayIQavBLL6LI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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