SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8474a1f453b2c6627379c8d2071aa0bf419691370fa22af1acc60ad036e54011' 
  AND token = '67giFyokcbZ2PJCGSHTns+jN0ReG5AQ1SrNaH2m9QyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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