SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a48b59e675108b5b85714832d88f2c76ba28a8ca20ab13c58b1a1cda68500a07' 
  AND token = 'e8ZUbnBCx1/8lOpKj1+6oYqYpfgP/2gJzNxwSuge+28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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