SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6aebbc2af03924ae62ea6b4ee0515e1e5b42cbfe414da2ff6268eca6683e80e' 
  AND token = 'qRxzdZGrEmuUNXpu4xR7hlBmC6jFZQBcH5PYffZ447Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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