SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fc2e42171381accb7184f8f2f66a223457db180e63a9b55be52a62dfe2242fd' 
  AND token = 'PVhlcADRFRt5dfY917Fu45RJqow8LwzNLIbhMoIGCnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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