SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8708f0068f7f2591c873cc495af67fd1683887a4ac9a0d67b9681f7b9d48e072' 
  AND token = 'meJnQ3LIhAVKXEIaJgSQG4F5B7p67U0kgP+r+TcW6Ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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