SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e76354157059a602cb9a74d1753418b5f978d45cdaf2b940994b4fa7e2602b27' 
  AND token = 'wU0roElnysH9vHP0phgOq8mpuce1G/fe5oAZ4jCafRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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