SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '578f865196eb6467ea0f58d193cacfef010c508e6d089135e436a88c8745d2b1' 
  AND token = '/f8vFPppgGyalDWAGID1grJkMvJdA1sBFpJqlMYiF1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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