SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3af03c2fd42f5f5949ae46742ef83ea9e745ed3c8c1f83e635c6c9ccf5312e03' 
  AND token = 'O2q3nQhg06KMmGflT1nNFNcOG8+2zlmzvWuH+/mFtrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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