SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b77b5d975d900079225045a1e6cf5268153a8545e89633ef0adf8fec13b7157b' 
  AND token = 'cNg0NnyqRy93nQimiYTC7kSH1RpYaEMKOkazAEg41AQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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