SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bc6b99912d8ce3891931ebaeec1ce85fd6c730799840e9e9fbce0e761a2379b' 
  AND token = 'JW10hk2hS6d6ocZ5dqWQwv2x0OU3iZRZNSBPw1pbNVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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