SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd064e20e9a33fbf2fa4907a1e909f0252dce64032ce84c9e20bb1aea1b281017' 
  AND token = '2+gRWUcuNcHerROrobneDLQcL/ao8smlLh6kQ2sAnUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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