SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5af942bcc03b7956b69b01c69616d7ee9d75b8cf3d62642de40c49add854c25' 
  AND token = 'nn9/ASTzJKeCoDgrVozSfYf7NwWaj3oPyARE1xjvLvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}