SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9945ce62fc3be154d192ea548e101915f3d237a6fe8e485636fb6444338846ce' 
  AND token = 'BElvL534Qkq+Px8k2Zz066i+ZJW1kzKpvfv733/pXQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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