SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '268d88ac62553329fc960ae459347f3b70e290552d2560ecd2b39e48bd0bcefd' 
  AND token = 'r+dmdNbPb4Cvm9POma7Pl0/V0fpDHinSbaPYigH64kI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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