SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc189d224d055b686cca7fdcb3086883b654e708ee2ea852270f1e9eff502576' 
  AND token = 'SAeekrH+Mbs7vF2beCVvChwTAIIVS6LpWOUdmeXZU68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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