SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f2ec077cce337d4cc9486d71587d8539c7ac0f422291e57bc1193aeea0d4d1d' 
  AND token = '77Cx3turn4mtOHCAawKbDOjxAauWBPTdxs84OFFPL4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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