SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4260af77e183e3d06fbc0e506b631d177150dfa80ef2e35d6e74136ea284b789' 
  AND token = 'v0a0ilMAnziHoHteDHJq1paNGHyRrPO3oOyzeOhp/NU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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