SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce81cbc74300f6fe06649a306d82b5830e12e0cc6f550b31e73ad1142c196953' 
  AND token = 'qEtHd7GOYTIr32JSa4Qk1AAbGUlIUCkFbTCDjOmHK3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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