SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f3651d02bd72799cd04583ee1b4e378e4c0305253d4a6958fd26add8be489ac' 
  AND token = 'JQLU4UOMhrEofuDyWyXR8u5QbnY7KaRBm0TnYgKTIHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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