SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5529a760d73626a2290ab9a17c574b66fd9b10c5a30db9758177ceafc27a3122' 
  AND token = '2BXiU9oMKd69ORayVkPAlyGsodQs0yUofzPdAu6ZaQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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